Emissions from internal combustion engines contribute significantly to the world's air quality problems. Many advances have been made in developing exhaust emissions control (‘aftertreatment’) devices and systems, using various types of filters, catalysts, and other types of reactors.
For example, many of today's gasoline engines, notably those of motor vehicles, are equipped with catalytic converters for emissions control. For diesel engines, various particulate filters and NOx traps are being developed.
Development and testing of various emissions aftertreatment devices may be performed by using them on actually operating engines, in the field or in a lab. Presently, for vehicle emissions testing, most testing occurs in specialized laboratories, where the vehicle is driven on a dynamo meter according to a prescribed driving cycle, such as I/M 240 or FTP for light and medium duty vehicles and CBD for heavy duty vehicles.
Another approach to testing emissions aftertreatment devices is to simulate the exhaust gas. The devices are then installed on a pipeline through which the simulated exhaust gas flows. The devices may be then subjected to conditions such as heat, to accurately simulate the actual conditions in which the device would operate.